The newest attraction at Louisville Mega Cavern, Mega Underground Bike Park just opened in February 2015 in addition to Mega Quest, opened in Fall 2013 and claims to be the only underground ropes challenge course in the world. The Mega Cavern, originally a limestone mine, was mined for 42 years, beginning in the 1930s, and is now the largest building in the state of Kentucky. The cavernous facility utilizes its 90-foot-high thoroughfares to unite guests with an exhilaration previously known only to highly caffeinated miners—Mega Zips.......ziplining in a cavern. Customers can purchase separate tickets for a variety of attractions. Open daily throughout the year. The Lights Under Louisville show running during the Christmas season, the Mega Tram, which runs beginning in mid-January through early October. During Mega Zips tours of up to two hours, amateur spelunkers will stream across the subterranean's six underground ziplines and dual racing lines under the sage supervision of the cavern's ACCT-certified experts. Along the way, guides will entertain guests with tales of the cavern’s rich history and uncanny impressions of stalagmites.